Even with the tabular example, which makes measurements a little more explicit, I can't find a elegant way to create a pill with corr(measured value from name in X, measured value from name in Y), which could solve the whole matrix - this might even be a too 'Excelee' way to think

Exactly, Beran's data was originally 32 x 11 values from which he makes a cross join in order to get 1:N data.

What I WAS trying to do was to follow on Jonathan Drummey 's footsteps (the Drawing with Numbers link above) to use only table calculations, like he himself did at the end of his post with Beran's original data, but now using the corr (or window_corr) from 10.2 instead of doing all the sigmas for correlation.

Just looking at your screenshot shown me that my approach would not work:

Pearson's formula is made of parcels available in table calc (or that can be assembled directly with table calculations)

...while the corr function asks for the measure itself which would only be available in the panel with "analyis -> aggregate measures" turned off, which would make even less sense to work with in this case.

So while self join can work with corr() easily (which now I believe was the intented use), domain completion may not be the use for it, albeit it being more gentle with larger tables.